Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three DNA restriction fragments of established sequence containing the Escherichia coli lac genetic controlling regions were cloned. In each case a recombinant plasmid was constructed which was suitable for the subsequent large scale purification of the lac fragment. A 789-base pair HindII fragment, containing the lac operator, promoter, and cyclic AMP receptor protein binding site, was ligated into the single HindII site of the amplifiable plasmid minicolicin E1 DNA (pVH51). A 203-base pair Hae III fragment containing the same genetic sites was ligated into the single Eco RI site of pVH51 which had been "filled in" by the Micrococcus luteus DNA polymerase. Thus, the lac fragment was inserted between two Eco RI sites. Plasmids containing multiple copies of this Eco RI fragment were then constructed. A 95-base pair Alu I fragment containing the lac promoter and operator was cloned similarly. Also, the 203-base pair fragment was cloned into the Eco RI site of pVH51 using a 300-base pair linker fragment (isolated by RPC-5 column chromatography) which permitted retention of its Hae III ends. Mapping studies on pVH51 DNA with a number of DNA restriction endonucleases, including Alu I, Taq I, and Hpa II, are described.
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PMID:Construction and mapping of recombinant plasmids used for the preparation of DNA fragments containing the Escherichia coli lactose operator and promoter. 37 10

DNA from chicken embryo nucleosome tetramers (about 760 base pairs in size) was enriched for tRNA genes by RPC-5 chromatography. The enriched DNA was hybridized with chicken embryo total tRNA and the hybridized DNA isolated utilizing a) avidinbiotin interaction, b) diazobenzyloxymethyl paper, and c) high temperature RPC-5 chromatography. The obtained single stranded DNA highly enriched for tRNA complementary sequences was hybridized with total DNA from nucleosome monomers (140--190 base pairs in size) and the excess of non hybridized monomer nucleosome DNA removed by Sepharose 4B chromatography. The hybrid molecules obtained were made fully double stranded by incubation with E. coli DNA polymerase I, DNA ligase, and exonuclease III. DNA was inserted into plasmid pBR322 by G-C joining procedure and the recombinant DNA used to transform the E. coli strain chi 1776. More than 70% of the transformants obtained hybridize to chicken embryo total tRNA.
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PMID:Cloning of chicken embryo tRNA genes using single stranded nucleosomal DNA highly enriched for tRNA complementary sequences. 49 22

Using partially purified mouse liver 23S mRNA known to be associated with the Ah locus and 3-methylcholanthrene-induced cytochrome P(1)-450, we synthesized double-stranded cDNA by the successive action of reverse transcriptase (RNA-directed DNA nucleotidyltransferase) and the Klenow A fragment of Escherichia coli DNA polymerase I. The double-stranded cDNA was inserted into pBR322 plasmid DNA by Pst I cleavage and homopolymeric "tailing" and cloned in E. coli LE392. Clone 46 hybridized with [(32)P]cDNA made from 23S mRNA from "Ah-responsive" C57BL/6N mice but did not hybridize with similarly prepared [(32)P]cDNA from "Ah-nonresponsive" DBA/2N mice. Clone 30 was positive, and clone 7 was negative, with both C57BL/6N and DBA/2N [(32)P]cDNA probes; these two clones were therefore used as "positive" and "negative" control clones, respectively. By translation-arrest experiments, clone 46 DNA and clone 30 DNA were shown to be associated with anti-P(1)-450- and anti-albumin-precipitable material, respectively. By agarose gel electrophoresis of Pst I digests, the clone 46 DNA insert was shown to be 1100 base pairs in total length and to contain one internal Pst I site. The cDNA made from total mRNA isolated from 3-methylcholanthrene-treated C57BL/6N mice hybridized to the two fragments of Pst I-digested DNA from clone 46, whereas similarly prepared cDNA from 3-methylcholanthrene-treated DBA/2N and control C57BL/6N and DBA/2N mice did not. Of 11 restriction endonucleases used, two (Pst I and Xba I) had sites within the clone 46 DNA insert. After hybridization of clone 46 (32)P-labeled nick-translated DNA to EcoRI fragments from A/HeJ mouse genomic DNA and fractionation by RPC-5 chromatography and gel electrophoresis, only one positive band (3-4 kilobase pairs appeared. These data demonstrate conclusively that pBR322 clone 46 DNA is associated with mRNA controlled by the murine Ah locus, presumably the structural gene encoding 3-methylcholanthrene-induced P(1)-450.
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PMID:Isolation and characterization of a cloned DNA sequence associated with the murine Ah locus and a 3-methylcholanthrene-induced form of cytochrome P-450. 626 72